propagation - Which HF bands are best during the day and which …
网页Lower frequency bands work best at night. Higher frequency bands work best during the day. The farther from 20m you get in either direction, the more pronounced these effects are. Of course, given that space weather is just as variable as Earth weather, there are exceptions to these rules every day.
How can you calculate the frequencies for each band?
网页2015年2月5日 · The frequency limits are a matter of the regulations that divide up the radio spectrum among many users. The limits of the amateur bands are semi-arbitrary. The common names for the bands ("20 m", "2 m", and so on) are simply the closest round number to the actual wavelengths. (In your example of …
What bands and modes will give me voice at 3,000 miles?
网页To pick 3 bands, 10,20 and 40m would work if you learned how propagation works. You can also build (from speaker wire) an antenna that will work pretty well on all three of those bands. "low power" means something special in the ham radio world. If you mean 5W transmit power, then you need to drop the voice mode from your requirements.
One dipole for multiple bands? - Amateur Radio Stack Exchange
网页Our modification to the G5RV and ZS6BKW antennas, while also somewhat of a compromise of frequency ranges and VSWR, lets us use all HF bands between 80 and 10 except 30 and 60* meters. (Details on the website above.) It depends on what bands you want to work. Choose your poison.
What are the relative bandwidths of the amateur bands?
网页2015年7月3日 · $\begingroup$ In Thailand where I live, the 160m band is 25kHz, the 80m band is 40kHz, the 40m band is 200kHz and the rest of the HF bands are 'normal'. There is no 6m band. There is no 6m band. Also - nobody mentioned the 4m band available in Europe, but there is mention of the 220Mhz band, available only in the US.
united states - Choosing simplex frequency as a technician
网页2014年4月4日 · I've redacted it somewhat to the bands most appropriate for simplex work. Note that depending on where you are, there might be large chunks of the repeater frequencies unused. Or you could live between two major metropolitan areas like me where there are NO unallocated repeater pairs...If they …
propagation - What is the cause of this unusually long period of ...
网页Bands were down, for the first several months figured it was temporary, even though repeatedly Space Weather had no proton showers or other anomalies to explain it. Been a ham for over 50 years, never remember anything like it. I've begun to suspect some sort of human activity is poisoning the ionosphere.
propagation - How do I find out what bands are open? - Amateur …
网页2014年7月23日 · $\begingroup$ The question in the title is not the one in the actual body of the question ... "how to find out what[sic] bands are open" is to check in all manner of places. I would start with the Cluster, for example. But the body of the question asks how you can guess which bands are open - which is a whole different thing. $\endgroup$
Can I reduce RFI/noise at the antenna?
网页Recently, the power was out in my neighborhood for an extended period of time. I fired up my HF rig using battery power and was amazed at the lack of noise across the HF bands. When the power grid came back online, the noise returned. The difference was drastic. S2 vs. S9 drastic. With that said, is there a good way to reduce RFI/noise at the ...
On which of these frequencies can I transmit without a license?
网页$\begingroup$ Not to mention public service bands, with default Chinese-seller programming (get one sold by the major American importer and it'll have this "fixed"). Seriously, either get rid of the radio, or use a programming cable and CHIRP software to disable transmission on all frequencies -- set up that way, those make decent police/fire ...